Cartridge handling system having shaped cartridge storage configuration

ABSTRACT

A cartridge handling system for storing and accessing at least one data cartridge according to the present invention may comprise a frame that defines at least one curvilinear cartridge access side. A curvilinear guide member is mounted to the frame so that substantially all points along the curvilinear guide member are positioned an equal spaced distance from the curvilinear cartridge access side defined by the frame. A cartridge access device is mounted to the curvilinear guide member so that a cartridge access end of the cartridge access device is positioned adjacent the curvilinear cartridge access side defined by the frame at substantially all positions along the curvilinear guide member. An actuator system operatively associated with the cartridge access device moves the cartridge access device along the curvilinear guide member.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This is a continuation of co-pending U.S. patent application Ser.No. 09/442,223, filed on Nov. 17, 1999, which is a continuation of U.S.patent application Ser. No. 09/045,134, filed Mar. 20, 1998, now U.S.Pat. No. 6,025,972, both of which are incorporated herein by referencefor all that they disclose.

FIELD OF INVENTION

[0002] This invention relates generally to data storage systems forhandling and storing data cartridges, such as optical disk or magnetictape cartridges, and more specifically to high density data storagesystems having increased data storage capacity.

BACKGROUND

[0003] Many different types of data storage and handling systems existand are being used to store data cartridges at known locations and toretrieve desired cartridges so that data may be written to or read fromthe data cartridges. Such data storage and handling systems are oftenreferred to as “juke box” data storage systems, particulary if they canaccommodate a large number of individual data cartridges.

[0004] A typical juke box data storage system may include one or moredifferent types of cartridge receiving devices for holding the variousdata cartridges. For example, one type of cartridge receiving device maycomprise a cartridge storage rack or “magazine” while another type ofcartridge receiving device may comprise a cartridge read/write device.The cartridge storage racks or magazines serve to provide storagelocations for the data cartridges and are commonly arranged so that theyform one or more vertical stacks. The cartridge read/write device may belocated adjacent the cartridge stack, although the cartridge read/writedevice may be positioned at any convenient location. The data storagesystem may also be provided with a cartridge access device for accessingthe various data cartridges contained in the cartridge receiving devicesand a positioning device for moving the cartridge access device amongthe cartridge receiving devices.

[0005] If a host computer system issues a request for data contained ona particular data cartridge, a control system associated with the datastorage system actuates the positioning system to move the cartridgeaccess device along the cartridge storage rack until the cartridgeaccess device is positioned adjacent the desired data cartridge. Thecartridge access device then removes the data cartridge from thecartridge storage rack and carries it to the cartridge read/writedevice. The cartridge access device inserts the selected data cartridgeinto the cartridge read/write device so that the host computer maythereafter read data from or write data to the data cartridge. After theread/write operation is complete, the cartridge access device may removethe data cartridge from the read/write device and return it to theappropriate location in the cartridge storage rack.

[0006] While data storage systems of the type described above work welland are currently being used, the continuing need to store everincreasing numbers of data cartridges can place significant limitationson the data storage system. For example, in data storage systems of thetype described above, the data cartridges may be stored in one or morevertical columns stacks which define a single cartridge access plane.While the data storage capacity of such a system may be increased byincreasing the number of data cartridges stored in the vertical columns,there is a limit to the maximum number of data cartridges that can bestored in a given column. That is, the higher the column (i.e., the moredata cartridges that are stored in the column), the longer it takes thedata access device to access a given data cartridge, particularly if thecartridge is located at one of the extreme ends of the column While morecolumns of shorter heights may be provided, this comes at the expenseand difficulty of providing a positioning system capable of moving thecartridge access device vertically along a given column or stack as wellas horizontally along the various rows of storage columns.

[0007] Partly in an effort to avoid the foregoing problems, data storagesystems have been developed that store the data cartridges in twoseparate stacks or columns that define two separate cartridge accessplanes. For example, the data cartridges may be arranged in a pair ofcolumns positioned on opposite sides of the cartridge access device. Ifthis arrangement is used, it is necessary to provide the cartridgeaccess device with a “pass-through” cartridge engaging assembly orpicker that is capable of accessing the data cartridges stored in bothstacks. Alternatively, such systems have been provided with “flipping”or rotating picker systems to access the data cartridges stored in bothstacks.

[0008] While the “multi-plane” data storage systems of the typedescribed above are currently being used, the pass-through, flipping, orrotating picker assemblies are relatively complex and expensive tomanufacture. Such picker assemblies also tend to suffer from decreasedreliability, primarily as a result of the relatively complex mechanicalstructure associated with such picker assemblies.

[0009] Another type of data storage system achieves the increasedstorage capacity associated with “multi-plane” data storage systemsdescribed above by arranging the data cartridges on a rotating magazinestack. While the rotating magazine stack usually does away with the needto provide a pass-through, flipping, or rotating picker, the mechanicalcomplexity of the data storage system is usually just transferred fromthe picker to the rotating magazine stack. Consequently, data storagesystems utilizing rotating magazine stacks often do not provide anysignificant advantages over “multi-plane” data storage systems thatutilize pass-through, flipping, or rotating pickers.

[0010] Another problem associated with data storage systems of the typedescribed above relates to the positioning system used to move thecartridge access device along the array of data cartridges. One type ofpositioning system, often referred to as a “lead-screw” system, mountsthe cartridge access device on a lead-screw, which when turned, movesthe cartridge access device up and down the array of cartridges.Unfortunately, the cantilever mounting arrangement that is often used tomount the cartridge access device on the lead-screw allows excessivetransverse or rotational movement of the cartridge access device whichtends to reduce positional accuracy and may make it difficult for thecartridge access device to engage the desired data cartridge.

[0011] One way to increase the stability of the cartridge access device,thus positional accuracy, of such a lead-screw positioning system is touse rigid guide rails to provide additional support to the cartridgeaccess device. Disadvantageously, the guide rails usually compriseprecision machined components which adds to the overall cost of the datastorage system. Further, such guide rail assemblies are often difficultto align, and may become mis-aligned during subsequent shipping ormovement of the data storage system, thereby requiring the positioningsystem to be re-aligned and re-calibrated before the data storage devicecan be placed in operation.

[0012] Consequently, a need remains for a data storage device havingincreased storage capacity but without the need for a pass-through,flipping, or rotating picker to access the data cartridges and withoutthe need to resort to a moving or rotating cartridge magazine stack.Ideally, such a data storage system would provide for increasedpositional accuracy to reduce errors due to misalignment of thecartridge access device but without the need for precision machinedguide rails. Still other advantages could be realized if the datastorage system reduced the time required for initial alignment andcalibration and provided increased immunity to subsequent mis-alignment,such as may occur during shipping or from rough handling.

SUMMARY OF THE INVENTION

[0013] A cartridge handling system for storing and accessing at leastone data cartridge according to the present invention may comprise aframe that defines at least one curvilinear cartridge access side. Acurvilinear guide member is mounted to the frame so that substantiallyall points along the curvilinear guide member are positioned an equalspaced distance from the curvilinear cartridge access side defined bythe frame. A cartridge access device is mounted to the curvilinear guidemember so that a cartridge access end of the cartridge access device ispositioned adjacent the curvilinear cartridge access side defined by theframe at substantially all positions along the curvilinear guide member.An actuator system operatively associated with the cartridge accessdevice moves the cartridge access device along the curvilinear guidemember.

BRIEF DESCRIPTION OF THE DRAWING

[0014] Illustrative and presently preferred embodiments of the inventionare shown in the accompanying drawing in which:

[0015]FIG. 1 is a plan view of a data storage system according to thepresent invention showing the cartridge access device in variouspositions;

[0016]FIG. 2 is a perspective view of the cartridge handling system thatmay be used in the data storage system shown in FIG. 1;

[0017]FIG. 3 is a side view in elevation of the frame assembly showingthe upper and lower plates and corresponding upper and lower guidechannels and gear racks;

[0018]FIG. 4 is a plan view of the lower plate of the frame assemblyshowing the lower U-shaped guide member and lower U-shaped gear rack;

[0019]FIG. 5 is a perspective view of a cartridge access device showingthe pinion drive system for moving the cartridge access device along theupper and lower guide members;

[0020]FIG. 6 is an enlarged side view in elevation of the actuatorsystem and lower bearing and wheel assembly of the cartridge accessdevice; and

[0021]FIG. 7 is an enlarged end view in elevation of the actuator systemand lower bearing and wheel assembly of the cartridge access device.

DETAILED DESCRIPTION OF THE INVENTION

[0022] A data storage system 10 according to the present invention isshown in FIG. 1 and may include a cartridge handling system 12 fortransferring data cartridges 14 between one or more cartridge receivingdevices, such as one or more cartridge storage racks or magazines 16 andone or more cartridge read/write devices 18. The various cartridgereceiving devices (e.g., the cartridge storage racks or magazines 16 andthe cartridge read/write devices 18) may be positioned at variouslocations around the cartridge handling system 12 so that they definethe generally U-shaped configuration shown in FIG. 1. Accordingly, thedata cartridges 14 may be accessed from three (3) cartridge accessplanes 41, 43, and 45.

[0023] The cartridge handling system 12 is best seen in FIG. 2 and maycomprise a frame assembly 26 which includes a lower or base plate 28 andan upper or top plate 30 that are held in generally parallel,spaced-apart relation by a support structure 72. The frame assembly 26of the cartridge handling system 12 may define a first cartridge accessside 20, a second cartridge access side 22, and a third cartridge accessside 24. The first and third cartridge access sides 20 and 24 may bepositioned in generally spaced-apart relation, whereas the secondcartridge access side 22 may be oriented generally transversely to thefirst and third cartridge access sides 20 and 24. The various cartridgereceiving devices may be positioned around the cartridge handling system12 so that the cartridge access planes 41, 43, and 45 defined by thecartridge receiving devices are located adjacent the three cartridgeaccess sides 20, 22, and 24.

[0024] The lower plate 28 of frame assembly 26 may include a lowerU-shaped guide member or channel 32 that forms a substantiallycontinuous member along the first, second, and third cartridge accesssides 20, 22, and 24 of the frame assembly 26. Similarly, the upperplate 30 may include an upper U-shaped guide member or channel 34 (FIG.3) that also forms a substantially continuous member along the first,second, and third cartridge access sides 20, 22, and 24 of the frameassembly 26.

[0025] The cartridge handling system 12 may also include a cartridgeaccess device 36 capable of loading and retrieving the data cartridges14 from the cartridge receiving devices (e.g., cartridge storage racks16 and the cartridge read/write devices 18). The cartridge access device36 engages the upper and lower U-shaped guide members or channels 32, 34in the respective lower and upper plates 28 and 30, and is thus guidedby the lower and upper guide members 32 and 34 along the first, second,and third cartridge access sides 20, 22, and 24. That is, the cartridgeengaging assembly 36 moves along a generally U-shaped path 40. Forexample, the cartridge access device 36 may be moved between a firstposition 38 adjacent the first access side 20 of frame assembly 26, asecond position 38′ adjacent the second access side 22, and a thirdposition 38″ adjacent the third access side 24, as best seen in FIG. 1.Of course, the cartridge access device 36 may also be moved from aposition adjacent the third cartridge access side 24 to positionsadjacent either the second cartridge access side 22 or the firstcartridge access side 20.

[0026] The cartridge access device 36 is moved along the lower and upperguide members 32 and 34 (i.e., following the U-shaped path 40) by anactuator system 42, as best seen in FIGS. 6 and 7. In one preferredembodiment, the actuator system 42 may comprise a rack and pinion drivesystem having a substantially continuous lower gear rack 44 provided onthe lower plate 28 at a position adjacent the lower U-shaped guidemember or channel 32. Accordingly, the lower gear rack 44 defines asubstantially continuous, U-shaped member. An upper gear rack 46 may beprovided on the upper plate 30 at a position adjacent the upper U-shapedguide member or channel 34. The upper gear rack 46 also defines asubstantially continuous, U-shaped member. Lower and upper drive pinions48 and 50 (FIG. 5) mounted to the cartridge access device 36 engage therespective lower and upper gear racks 44 and 46. A pinion drive assembly52 mounted to the cartridge access device 36 rotates the lower and upperpinion gears 48 and 50, thereby moving the cartridge access device 36back and fourth along the lower and upper guide members 32, 34,following the U-shaped path 40. See FIG. 1.

[0027] In operation, the data storage system 10 according to the presentinvention may be used to transfer a plurality of data cartridges 14between the various cartridge receiving devices (e.g., cartridge storageracks or magazines 16 and the cartridge read/write devices 18)positioned adjacent the first, second, and third cartridge access sides20, 22, and 24. For example, the data storage system 10 may be used by ahost computer system (not shown) or other data processing system tostore and access data contained in the data cartridges 14. If the hostcomputer system (not shown) issues a request for data stored on aparticular data cartridge 14, a control system (not shown) associatedwith the data storage system 10 operates the actuator system 42 on thecartridge access device 36 as necessary to move the cartridge accessdevice 36 along the U-shaped path 40 until the cartridge access device36 is located adjacent the appropriate data cartridge 14.

[0028] Consider, for example, an initial condition wherein the desireddata cartridge 14 is stored in one of the cartridge storage racks ormagazines 16. Upon receiving a request for the data cartridge 14 fromthe host computer system (not shown), the control system (not shown)operates the actuator system 42 to move the cartridge access device 36along the U-shaped path 40 until the cartridge access device 36 isadjacent the selected data cartridge 14 in the storage rack 16. Acartridge engaging device or “picker” (not shown) associated with thecartridge access device 36 then engages the data cartridge 14 and drawsit into the cartridge access device 36. The actuator system 42 thenactuates the pinion drive assembly 52 as necessary to move the cartridgeaccess device 36 to a desired cartridge read/write device 18. Onceproperly positioned adjacent the desired cartridge read/write device 18,the cartridge engaging assembly or picker (not shown) associated withthe cartridge access device 36 loads the data cartridge 14 into thecartridge read/write device 18. The host computer system (not shown) maythen access the data on the data cartridge 14 in the conventionalmanner.

[0029] When the data cartridge 14 is no longer needed, the controlsystem (not shown) may operate the actuator system 42 to move thecartridge access device 36 along the U-shaped path 40 until thecartridge access device 36 is again located at a position adjacent thecartridge read/write device 18 (if the cartridge access device 36 is notalready located in the appropriate position). Thereafter, the cartridgeengaging assembly or picker (not shown) may retrieve the data cartridge14 from the cartridge read/write device 18. The cartridge access device36 may then return the data cartridge 14 to its appropriate location inthe cartridge storage racks or magazines 16.

[0030] A significant advantage of the data storage system 10 accordingto the present invention is that it provides access to two or moreplanes (e.g., planes 41, 43, and 45) defined by cartridge receivingdevices (e.g., cartridge storage racks or magazines 16 and/or cartridgeread/write devices 18), but without the need to resort to“pass-through,” “flipping,” or “rotating” type cartridge engaging or“picker” devices, which are mechanically complex and may be expensiveand unreliable. The data storage system 10 also provides access to twoor more planes (e.g., 41, 43, and 45) of cartridge receiving devices,but without the need to use moving or rotating cartridge magazinestacks. Accordingly, the present invention provides high cartridge(i.e., data storage) density, while at the same time substantiallyreducing the mechanical complexity of the data storage system. Anotheradvantage of the data storage system 10 according to the presentinvention is that it provides for improved user access to the cartridgemagazines by allowing the same to be loaded and removed from one side ofthe data storage system 10.

[0031] Having briefly described the data storage system 10 according tothe present invention, as well as some of its more significant featuresand advantages, the various embodiments of the data storage system willnow be described in detail. However, before proceeding with the detaileddescription, it should be noted that while the data storage system 10 isshown and described herein as it could be used to store and retrievemagnetic data cartridges 14 having a certain size and configuration(e.g., DLT or digital linear tape cartridges), it is not limited to anyparticular type of data cartridge. Indeed, the data storage system 10according to the present invention could be used with any type of datastorage device comprising any type of data storage medium (e.g.,magnetic disk or tape, optical disk, etc.). Consequently, the presentinvention should not be regarded as limited to use with the particulartype and style of data cartridge 14 shown and described herein.

[0032] Referring back now to FIG. 1, one embodiment 10 of the datastorage system according to the present invention may comprise a mainhousing or chassis 54 configured to hold the various components of thedata storage system 10. For example, in one preferred embodiment, themain housing or chassis 54 may comprise a generally rectangularly shapedstructure adapted to receive the cartridge handling system 12, and oneor more cartridge receiving devices, such as one or more cartridgestorage racks or magazines 16 and one or more cartridge read/writedevices 18. The housing or chassis 54 may also be adapted to receive anyof a wide range of other components or devices (e.g., control systems,power supplies, etc.) well-known in the art and that may be required ordesired for the operation of the data storage system 10. The housing orchassis 54 may also be provided with a cartridge magazine access end 56to allow a user (not shown) to access the cartridge storage racks ormagazines 16. An access door (not shown) may be provided on the accessend 56 to provide access to the cartridge magazines 16. In one preferredembodiment, the housing or chassis 54 is sized to be received by astandard storage rack system (not shown), such as an EIA rack assemblyavailable from Crenlo Corp. of Minnesota (USA), although this is notrequired.

[0033] In one preferred embodiment, the cartridge handling system 12 maycomprise a generally rectangularly shaped structure having a firstcartridge access side 20, a second cartridge access side 22, and a thirdcartridge access side 24. As used herein, the term “cartridge accessside” refers to any side of the cartridge handling system 12 from whichdata cartridges 14 may be accessed, either from a cartridge storage rackor magazine 16 or a cartridge read/write device 18.

[0034] The cartridge handling system 12 defines the general arrangementof the cartridge access planes associated with the cartridge receivingdevices (e.g., the cartridge storage racks or magazines 16 and thecartridge read/write devices 18). That is, the cartridge receivingdevices should be arranged around the cartridge handling system 12 sothat the cartridge access planes defined by the cartridge receivingdevices are located at positions adjacent the cartridge access sides ofthe cartridge handling system 12. For example, in one preferredembodiment, the various cartridge receiving devices (e.g., the cartridgestorage racks or magazines 16 and cartridge read/write devices 18) arearranged around the cartridge handling system 12 so that first cartridgeaccess plane 41 is positioned adjacent the first cartridge access side20, the second cartridge access plane 43 is positioned adjacent thesecond cartridge access side 22, and the third cartridge access plane 45is positioned adjacent the third cartridge access side 24.

[0035] In accordance with the forgoing considerations, the variouscartridge receiving devices (e.g., the cartridge storage racks ormagazines 16 and the cartridge read/write devices 18) may be locatedadjacent any cartridge access side (e.g., 20, 22, and 24) of thecartridge handling system 12 in any of a wide variety of arrangements.For example, in one preferred embodiment, two cartridge storage racks ormagazines 16 are located adjacent the first cartridge access side 20 ofthe cartridge handling system 12, whereas another pair of magazines 16are located adjacent the third cartridge access side 24. A pair ofcartridge read/write devices or “drives” 18 are located adjacent thesecond cartridge access side 22 of the cartridge handling system 12. SeeFIG. 1. Alternatively, a greater or lesser number of cartridge storageracks 16 could be provided, or the cartridge read/write devices 18 couldbe located adjacent either or both of the first or third cartridgeaccess sides 20 and 24.

[0036] The U-shaped arrangement of the cartridge storage magazines 16and cartridge read/write devices 18 just described and shown in FIG. 1for one preferred embodiment allows the various cartridge storage racksor magazines 16 to be easily accessed by a user (not shown) from thecartridge access end 56 of the chassis or housing assembly 54. That is,the user may replace the various magazines 16 from time to time toprovide different data cartridges 14 to the data storage system 10.Alternatively, of course, the various cartridge storage racks ormagazines 16 and cartridge read/write devices 18 could be configuredaround the cartridge handling system 12 in any other convenientarrangement depending on the requirements of the particular application.

[0037] Continuing now with the description, the details of the cartridgehandling system 12 are best seen in FIGS. 2-4, with occasional referenceto FIG. 1. In one embodiment, the cartridge handling system 12 comprisesa generally rectangular structure or frame assembly 26 that includes alower or base plate 28, an upper or top plate 30, and a supportstructure 72. The support structure 72 holds or positions the lowerplate 28 and upper plate 30 in generally parallel, spaced-apartrelation, as best seen in FIG. 2. The frame assembly 26 defines a firstcartridge access side 20, a second cartridge access side 22, and a thirdcartridge access side 24. The first and third cartridge access sides 20and 24 are positioned in spaced-apart relation, whereas the secondcartridge access side 22 is positioned generally transversely to thefirst and third cartridge access sides 20 and 24. Accordingly, the threecartridge access sides 20, 22, and 24 define a generally U-shapedconfiguration about which the various cartridge magazines 16 andread/write devices 18 may be arranged. See FIG. 1. Alternatively,however, the various cartridge access sides 20, 22, and 24 could bearranged in other configurations.

[0038] For example, instead of being positioned at substantially rightangles to one another, the various cartridge access sides 20, 22, and 24could be positioned so that they form oblique (i.e., non-perpendicular)angles with respect to one another, such as would be the case if theframe assembly 26 comprised a pentagonal (5-sided) or hexagonal(6-sided) configuration. In still another alternative, the cartridgeaccess sides 20, 22, and 24 need not comprise straight segments, butcould instead comprise curvilinear segments or portions, such as may bethe case if the frame assembly 26 were provided with a circular orsemi-circular cross-section. Consequently, the present invention shouldnot be regarded as limited to a frame assembly 26 having cartridgeaccess sides 20, 22, and 24 arranged according to the geometricalconfigurations shown and described herein.

[0039] The lower plate 28 is best seen in FIGS. 3 and 4 and may comprisea plate-like, generally rectangular member that includes a lower guidemember or channel 32 therein. The lower guide member or channel 32 maycomprise a first elongate section 58 located adjacent the firstcartridge access side 20 and a second elongate section 60 locatedadjacent the second cartridge access side 22. The lower guide member orchannel 32 may also include a third elongate section 62 that is locatedadjacent the third cartridge access side 24. The second elongate section60 is joined to the first and third elongate sections 58 and 62 byrespective rounded corner sections 64 and 66. Accordingly, the first,second, and third elongate sections 58, 60, and 62 define asubstantially continuous guide member 32 that extends along the threecartridge access sides 20, 22, and 24 of the cartridge handling system12.

[0040] The upper plate 30 is essentially identical to the lower plate 28just described and may comprise a plate-like, generally rectangularmember having an upper U-shaped guide member or channel 34 therein. Theupper U-shaped guide member 34 may include first and third elongatesections 68 and 70 that are located adjacent the respective first andthird cartridge access ends 20 and 24. See FIG. 3. The upper guidemember or channel 34 may also include a second elongate section (notshown) located adjacent the second cartridge access side 22. The secondelongate section (not shown) of the upper guide member or channel 34 isconnected to the first and third elongate sections 68 and 70 byrespective rounded corner sections (not shown) in a manner essentiallyidentical to those of the lower guide member 32 in the lower plate 28.

[0041] The lower and upper plates 28 and 30 may be made from any of awide range of materials, such as metals or plastics, suitable for theintended application. By way of example, in one preferred embodiment,the lower and upper plates 28 and 30 are molded as single pieces from apolycarbonate plastic material, although other materials could also beused. The lower and upper guide members or channels 32 and 34 formedwithin the lower and upper plates 28 and 30 may have any of a wide rangeof widths and depths suitable for the intended application. In onepreferred embodiment, both lower and upper guide channels 32 and 34 havewidths of about 7.16 mm and depths of about 6.0 mm.

[0042] The support structure 72 for holding the lower and upper plates28 and 30 in essentially parallel, spaced-apart relation may be madefrom any of a wide range of materials, such as metals or plastics,suitable for the intended application. In one preferred embodiment, thesupport structure 72 is fabricated from sheet metal and is secured tothe lower and upper plates 28 and 30 by any convenient fastener systemor device (e.g., screws).

[0043] The cartridge access device 36 is best seen in FIGS. 2 and 5 andmay comprise a structure sized to receive the data cartridges 14(FIG. 1) used in the data storage system 10. The cartridge access device36 may also be provided with a cartridge engaging assembly or “picker”(not shown) suitable for loading and retrieving the data cartridges 14to and from the particular cartridge receiving device (e.g., cartridgestorage rack 14 or cartridge read/write device 18) in which the datacartridge 14 is held. Examples of cartridge engaging assemblies or“pickers” suitable for use in the present invention are disclosed in thefollowing U.S. Pat. Nos. which are specifically incorporated byreference herein for all that they disclose: 4,998,232 entitled “OpticalDisk Handling Apparatus with Flip Latch;” 5,010,536 entitled “CartridgeHandling System;” 5,014,255 entitled “Optical Disk Cartridge HandlingApparatus with Passive Cartridge Engagement Assembly;” and 5,043,962entitled “Cartridge Handling System.” Alternatively, any of a wide rangeof other types of cartridge engaging assemblies or pickers that arewell-known in the art also may be used in the present invention. In anyevent, since such cartridge engaging assemblies or “pickers” arewell-known in the art and are not necessary in understanding the presentinvention, the particular cartridge engaging assembly utilized in onepreferred embodiment of the invention will not be described in furtherdetail.

[0044] Regardless of the particular type of style of cartridge engagingassembly or “picker” that is utilized in the cartridge access device 36,the cartridge access device 36 may be mounted to the lower and upperU-shaped guide members 32 and 34 so that the cartridge access device 36may be moved along the first, second and third cartridge access sides20, 22, and 24 generally following the U-shaped path 40. See FIG. 1.More specifically, the cartridge access device 36 may be retained in thelower U-shaped guide member or channel 32 by a pair of lower bushingmembers 74 and 76 that extend from the bottom 78 of the cartridge accessend 80 of the cartridge access device 36. In one preferred embodiment,the lower bushing member 74 may be attached to a shaft 82 that may bemounted to the gear case cover (not shown) for the gear case housing 23.Alternatively, other mounting arrangements could be used to attach thelower bushing member 74 to the cartridge access device 36, as would beobvious to persons having ordinary skill in the art. The lower bushingmember 76 may be attached to the end of the lower pinion 48, in themanner best seen in FIG. 5, or may even comprise an integral portion ofthe lower pinion 48.

[0045] The top end 84 of the cartridge access device 36 may be providedwith a pair of upper bushing members 86 and 88 that are sized to beslidably received in the upper U-shaped guide member or channel 34. Theupper bushing 86 may be mounted to the top end 84 of the cartridgeaccess end 80 of cartridge access device 36. The upper bushing 88 may bemounted to the end of the upper pinion 50, or may even comprise anintegral portion of the upper pinion 50. The lower and upper bushings74, 76, 86, and 88 guide the cartridge access device 36 along the lowerand upper guide members 32 and 34 associated with the lower and upperplates 28 and 30. Finally, the bottom end 78 of cartridge access device36 may be provided with a guide wheel 90 which contacts the lower plate28 and supports the weight of the cartridge access device 36. See FIGS.6 and 7. Optionally, the distal end 92 of the cartridge access device 36also may be provided with a similar wheel arrangement (not shown) tosupport the distal end 92 of the cartridge access device 36.

[0046] The lower and upper bushing members 74, 76, 86, and 88 may bemade from any of a wide range of materials, such as metals or plastics(e.g., brass or nylon), suitable for providing a low friction engagementwith the respective lower and upper guide members or channels 32, 34 inthe respective lower and upper plates 28 and 30. In one preferredembodiment, the lower and upper bushing members 74, 76, 86, and 88 aremade from nylon and have diameters of about 7.01 mm which provides 0.15mm of clearance between the bushing members and the guide channels,which, as mentioned above, have widths of about 7.16 mm.

[0047] As was briefly described above, the cartridge access device 36 ismoved along the lower and upper guide members 32 and 34 by an actuatorsystem 42, as best seen in FIGS. 3-7. In one preferred embodiment, theactuator system 42 may comprise a rack and pinion drive system having asubstantially continuous lower gear rack 44 provided on the lower plate28 at a position adjacent the lower U-shaped guide member or channel 32.Similarly, a substantially continuous upper gear rack 46 may be providedon the upper plate 30 at a position adjacent the upper U-shaped guidemember or channel 34. Lower and upper drive pinions 48 and 50 (FIG. 5)mounted to the cartridge access device 36 engage the respective lowerand upper gear racks 44 and 46. The pinion drive assembly 52 mounted tothe cartridge access device 36 rotates the lower and upper pinion gears48 and 50 to move the cartridge access device 36 back and fourth alongthe U-shaped path 40, as best seen in FIG. 1.

[0048] Referring now specifically to FIGS. 3 and 4, the lower gear rack44 may comprise first and second elongate sections 92 and 94 that areprovided on the lower plate 28 adjacent the first and second elongatesections 58 and 60 of the lower guide member or channel 32. A thirdelongate section 96 may be provided on the lower plate 28 at a positionadjacent the third elongate section 62 of lower guide member 32. Thesecond elongate section 94 of lower gear rack 44 may be joined to thefirst and third elongate sections 92 and 96 of lower gear rack 44 byrespective rounded corner sections 97, 98, as best seen in FIG. 4. Thelower gear rack 44 may therefore comprise a substantially continuous,U-shaped member that extends along substantially the entirety of thelower U-shaped guide member or channel 32, again as best seen in FIG. 4.

[0049] The upper gear rack 46 is essentially identical to the lower gearrack 44 just described and may include first and third elongate sections91 and 95 that are provided on the upper plate 30 at positions adjacentthe respective first and third elongate sections 68 and 70 of the upperguide member or channel 34. A second elongate section 93 may be providedon the upper plate 30 at a position adjacent the second elongate section(not shown) of upper guide member 34. The second elongate section 93 ofupper gear rack 46 may be connected to the first and third elongatesections 91 and 95 of upper gear rack 46 by respective rounded cornersections 89 and 99, as best seen in FIG. 3. The upper gear rack 46 maytherefore comprise a substantially continuous, U-shaped member thatextends along substantially the entirety of the upper U-shaped guidemember or channel 34.

[0050] The lower and upper gear racks 44 and 46 may be made from any ofa wide variety of materials, such as metals or plastics, suitable forthe intended application. By way of example, in one preferred embodimentwherein the lower and upper plates 28 and 30 are molded from apolycarbonate plastic material, the lower and upper gear racks 44 and 46are provided as integrally molded portions of the lower and upper plates28 and 30 (i.e., the lower and upper gear racks 44 and 46 comprise thepolycarbonate plastic material). Alternatively, the lower and upper gearracks 44 and 46 may comprise separate components that are then fixedlyattached to the lower and upper plates 28 and 30 by any of a wide rangeof fastening systems or devices (e.g., adhesives, screws, rivets, etc.).

[0051] The lower and upper gear racks 44 and 46 may be provided with anyconvenient tooth pitch suitable for the intended application. In onepreferred embodiment, the lower and upper gear racks 44 and 46 may havea tooth pitch of about 32 (teeth/inch), although other tooth pitches mayalso be used.

[0052] Referring now to FIG. 5, the cartridge access device 36 may beprovided with lower and upper pinion gears 48 and 50 which engage thelower and upper gear racks 44 and 46, respectively. The lower and upperpinion gears 48 and 50 may be mounted to a drive shaft assembly 15 whichmay be journalled for rotation in the cartridge access device 36. By wayof example, in one preferred embodiment, the upper end 17 of drive shaftassembly 15 is journalled for rotation in an upper bearing member 19.The lower end 21 of drive shaft 15 may be journalled for rotation in thegear case cover (not shown) for gear case housing 23. Alternatively,other mounting arrangements are possible, as would be obvious to personshaving ordinary skill in the art.

[0053] As was described above, the lower and upper bushings 76 and 88may be mounted to the ends of the respective lower and upper piniongears 48 and 50. Alternatively, the lower and upper bushings 76 and 88may be mounted directly to the upper and lower ends 17 and 21 of driveshaft assembly 15.

[0054] The lower and upper drive pinions 48 and 50 are driven by apinion drive assembly 52 that may be mounted to the cartridge accessdevice 36. Referring now primarily to FIGS. 5-7, the pinion driveassembly 52 may comprise a motor 25 and a reduction gear assembly 27mounted within gearbox housing 23. The reduction gear assembly 27 maycomprise one or more spur gears for reducing the speed of the motor 25.The drive shaft assembly 15 may be operatively connected to the outputpinion 29 of reduction gear assembly 27 by a face gear 31.Alternatively, other types of right angle gear arrangements may be used.

[0055] In one preferred embodiment, the reduction gear assembly 27 maybe provided with a encoder system (not shown) to monitor the angularposition of a selected gear in the reduction gear assembly 27. Theangular position of the selected gear provided by the encoder system(not shown) may be used by the control system (not shown) to deriveinformation about the position, velocity, and acceleration of thecartridge access device 36. However, since such encoder systems arewell-known in the art and could be easily provided by persons havingordinary skill in the art after having become familiar with theteachings of the present invention, the particular encoder systemutilized in one preferred embodiment of the present invention will notbe described in further detail.

[0056] The reduction gear assembly 27 may comprise any of a wide varietyof gear reduction systems, such as spur gear reduction systems,well-known in the art. Alternatively, a worm gear reduction system (notshown) could also be used. The motor 25 may comprise a permanent magnetd.c. motor, such as type RS-385PH, available from Mabuchi Motor Corp. ofChina. Alternatively, other types of motors may be provided. Of course,the characteristics of the particular type of motor that is selectedwill determine the reduction ratio that is provided by the reductiongear assembly 27. In one preferred embodiment, the reduction gearassembly 27 provides a reduction ratio of about 12:1, although otherreduction ratios may be used.

[0057] In an alternative embodiment, other types of actuator systems 42may be used to move the cartridge access device 36 along the lower andupper guide members or channels 32 and 34. For example, a chain or beltdrive arrangement could be used to connect the motor 25 and thecartridge access device 36 to move the cartridge access device along thelower and upper guide members or channels 32 and 34. In yet anotherarrangement, a wire rope or “cable” and pulley arrangement may be usedto connect the cartridge access device 36 to the motor 25.

[0058] As was mentioned above, the data storage system 10 may beprovided with a control system (not shown) suitable for controlling,among other things, the actuator system 42 associated with the cartridgehandling system 12. For example, such a control system would operate theactuator system 42 to move the cartridge access device 36 along theU-shaped path 40 (FIG. 1) so that the cartridge access device 36 mayaccess the desired data cartridge 14 from either the cartridge storagerack or magazine 16 or the cartridge read/write device 18, as the casemay be. However, since such control systems are well-known in the artand could be readily provided by persons having ordinary skill in theart, the particular control system used to control the operation of theactuator system 42 will not be described in further detail herein.

[0059] The data storage system 10 invention may be used to transfer aplurality of data cartridges 14 between the cartridge storage racks ormagazines 16 and the cartridge read/write devices 18. For example, thedata storage system 10 may be used by a computer system (not shown), orother data processing system, to store and access data contained in thedata cartridges 14. If the computer system (not shown) issues a requestfor data stored on a particular data cartridge 14, the control system(not shown) associated with the data storage system 10 operates theactuator system 42 on the cartridge access device 36 as necessary tomove the cartridge access device 36 along the U-shaped path 40 until thecartridge access end 80 of the cartridge access device 36 is locatedadjacent the appropriate data cartridge 14.

[0060] For example, if the desired data cartridge 14 is stored in one ofthe cartridge storage racks or magazines 16, then the actuator system 42moves the cartridge access device 36 until the cartridge access end 80is directly opposite the selected data cartridge 14. The cartridgeengaging device or “picker” (not shown) associated with the cartridgeaccess device 36 then engages the data cartridge 14 and draws it intothe cartridge access device 36. Once the data cartridge 14 has beencompletely drawn into the cartridge access device 36, the actuatorsystem 42 actuates the pinion drive assembly 52 as necessary to move thecartridge access device 36 to the desired cartridge read/write device18. Once properly positioned adjacent the desired cartridge read/writedevice 18, the cartridge picker (not shown) loads the data cartridge 14into the cartridge read/write device 18. The computer system (not shown)may then access the data on the data cartridge 14 in the conventionalmanner.

[0061] When the data cartridge 14 is no longer needed, the controlsystem (not shown) would then move the cartridge access device 36 alongthe U-shaped path 40 to position the cartridge access end 80 of thecartridge access device 36 opposite the cartridge read/write device 18(if the cartridge access device 36 is not already located in theappropriate position). Thereafter, the cartridge picker (not shown) mayretrieve the data cartridge 14 from the cartridge read/write device 18.The cartridge access device 36 may then return the data cartridge 14 toits appropriate location in the cartridge storage racks or magazines 16.

[0062] It is contemplated that the inventive concepts herein describedmay be variously otherwise embodied and it is intended that the appendedclaims be construed to include alternative embodiments of the inventionexcept insofar as limited by the prior art.

What is claimed is:
 1. A cartridge handling system for storing andaccessing at least one data cartridge, comprising: a frame defining atleast one curvilinear cartridge access side; a curvilinear guide membermounted to said frame so that substantially all points along saidcurvilinear guide member are positioned an equal spaced distance fromthe curvilinear cartridge access side defined by said frame; a cartridgeaccess device having a cartridge access end, said cartridge accessdevice engaging said curvilinear guide member so that the cartridgeaccess end of said cartridge access device is positioned adjacent thecurvilinear cartridge access side defined by said frame at substantiallyall positions along said curvilinear guide member; and an actuatorsystem operatively associated with said cartridge access device formoving said cartridge access device along said curvilinear guide member.2. The cartridge handling system of claim 1 , wherein said actuatorsystem comprises: a substantially continuous gear rack having acurvilinear shape so that said substantially continuous gear rack ispositioned a constant spaced distance from the curvilinear access sidedefined by said frame; a pinion gear mounted for rotation on saidcartridge access device, said pinion gear engaging said gear rack; and amotor operatively associated with said pinion gear for rotating saidpinion gear to cause said cartridge access device to move along saidcurvilinear guide member.
 3. The cartridge handling system of claim 2 ,wherein said curvilinear guide member comprises a curvilinear channeland wherein said cartridge access device includes a bearing member thatengages said curvilinear channel.
 4. The cartridge handling system ofclaim 2 , wherein said curvilinear guide member comprises asemi-circular section.
 5. A cartridge handling system for storing andaccessing at least one data cartridge, comprising: a frame defining afirst cartridge access side and a second cartridge access side, thefirst and second cartridge access sides being substantially straight; aguide member mounted to said frame, said guide member comprising a firststraight section located adjacent the first cartridge access side ofsaid frame, a second straight section located adjacent the secondcartridge access side of said frame, and a curved section connecting thefirst and second straight sections so that said guide member comprises asubstantially continuous member having at least one straight section andat least one; a cartridge access device having a cartridge access end,said cartridge access device engaging said guide member so that thecartridge access end is adjacent the first cartridge access side whensaid cartridge access device is located on the first straight section ofsaid guide member and so that the cartridge access end is adjacent thesecond cartridge access side when said cartridge access device islocated on the second straight section of said guide member; and anactuator system operatively associated with said cartridge access devicefor moving said cartridge access device along said guide member.
 6. Thecartridge handing system of claim 5 , wherein the second cartridgeaccess side defined by said frame defines an oblique angle with respectto the first cartridge access side defined by said frame.
 7. Thecartridge handling system of claim 6 , wherein said frame defines athird cartridge access side, the third cartridge access side beingsubstantially straight and defining an oblique angle with respect to thesecond cartridge access side and wherein said guide member comprises athird straight section located adjacent the second cartridge access sideof said frame and a second curved section connecting the second andthird straight sections so that said guide member comprises asubstantially continuous member.
 8. A cartridge handling system forstoring and accessing at least one data cartridge, comprising: acurvilinear guide member defining at least one curvilinear cartridgeaccess side; a cartridge access device having a cartridge access end,said cartridge access device engaging said curvilinear guide member; asubstantially continuous gear rack having a curvilinear shape so thatsaid substantially continuous gear rack is positioned a constant spaceddistance from said curvilinear guide member; a pinion gear mounted forrotation on said cartridge access device, said pinion gear engaging saidsubstantially continuous gear rack; and a motor operatively associatedwith said pinion gear for rotating said pinion gear to cause saidcartridge access device to move along said curvilinear guide member. 9.A cartridge handling system for storing and accessing at least one datacartridge, comprising: curvilinear guide member means for defining atleast one curvilinear cartridge access side; cartridge access means formoving along said curvilinear guide member means and for accessing adata cartridge positioned adjacent the at least one curvilinearcartridge access side; actuator means operatively associated with saidcartridge access means for moving said cartridge access means along saidcurvilinear guide member means.
 10. A cartridge handling system forstoring and accessing at least one data cartridge, comprising: a framesized to receive the at least one data cartridge; a curved guide membermounted to said frame; a cartridge access device having a cartridgeaccess end, said cartridge access device engaging said curved guidemember so that the cartridge access end of said cartridge access devicemoves along a curved displacement path, the at least one data cartridgebeing positioned along the curved displacement path so that the at leastone data cartridge can be accessed by said cartridge access device; andan actuator system operatively associated with said cartridge accessdevice, said actuator system moving said cartridge access device alongsaid curved guide member.
 11. The cartridge handling system of claim 10, wherein said frame is sized to receive a plurality of data cartridgespositioned adjacent the curved displacement path so that individual onesof the plurality of data cartridges can be selectively accessed by saidcartridge access device.
 12. The cartridge handling system of claim 11 ,wherein said curved guide member comprises a curved channel and whereinsaid cartridge access device includes a bearing member that engages saidcurved channel.
 13. The cartridge handling system of claim 12 , whereinsaid actuator system comprises: a substantially continuous gear rackhaving a curved shape so that said substantially continuous gear rack ispositioned a uniform spaced distance from said curved guide member; apinion gear mounted for rotation on said cartridge access device, saidpinion gear engaging said gear rack; and a motor operatively associatedwith said pinion gear for rotating said pinion gear to cause saidcartridge access device to move along said curved guide member.
 14. Acartridge handling system for storing and accessing at least one datacartridge, comprising: a frame sized to receive the at least one datacartridge; a guide member mounted to said frame, said guide memberincluding at least one straight section and at least one curved section;a cartridge access device having a cartridge access end, said cartridgeaccess device engaging said guide member so that the cartridge accessend of said cartridge access device moves along a displacement pathhaving at least one straight section and at least one curved section,the at least one data cartridge being positioned along the displacementpath so that the at least one data cartridge can be accessed by saidcartridge access device; and an actuator system operatively associatedwith said cartridge access device, said actuator system moving saidcartridge access device along said guide member.
 15. The cartridgehandling system of claim 14 , wherein said frame is sized to receive aplurality of data cartridges positioned along the displacement path sothat individual ones of the plurality of data cartridges can beselectively accessed by said cartridge access device.
 16. The cartridgehandling system of claim 15 , wherein said guide member comprises achannel portion having at least one straight section and at least onecurved section and wherein said cartridge access device includes abearing member that engages said channel portion.
 17. The cartridgehandling system of claim 16 , wherein said actuator system comprises: asubstantially continuous gear rack having at least one straight sectionand at least one curved section so that said substantially continuousgear rack is positioned a uniform spaced distance from the respectivestraight and curved sections of said guide member; a pinion gear mountedfor rotation on said cartridge access device, said pinion gear engagingsaid gear rack; and a motor operatively associated with said pinion gearfor rotating said pinion gear to cause said cartridge access device tomove along said guide member.